Field of the Disclosure
The present disclosure, for example, relates to wireless communication systems, and more particularly to joint channel and phase noise estimation.
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).
Phase noise (PN) is commonly present in wireless transmissions. PN can lead to errors in channel estimation, degrade signal quality, and increase intercarrier interference among subcarriers, among other problems. Some radios, such as millimeter wave (mmW) radios, have higher phase noise levels than other radios, such as those using frequencies below 6 gigahertz (GHZ). This may be due to a higher frequency ratio between a local oscillator and a temperature compensated crystal oscillator of the radio. Such radios may also have noisier voltage control oscillators. In a downlink or uplink transmission, a user equipment (UE) may contribute a majority of the PN.
Performing channel estimation may be necessary for coherent detection of wireless transmissions. However, the channel estimate and the PN may be unknown during the reception of a control symbol. The channel estimate and the estimated PN may be used to demodulate control and data symbols.